Structural features and photoluminescence behaviors of color-temperature tunable (Gd,Y)3Al5O12:Ce3+/Cr3+ phosphors with varying compositions

Insights into the roles of the MgO additive in crystal structures, sintering behaviors, and optical properties of transparent In2O3 semiconductor ceramics

“…The attenuation curves were obtained employing a single exponential equation to determine the fluorescence lifetimes, which is expressed as eqn (6): I = A exp(− t / τ ) + B where I is a function of the luminescence intensity, τ is the fluorescence lifetime, t is the decay time, and A and B are constants. 46–50 The detailed fitting parameters are listed in Table 3. For the 493 nm DL emission, the resulting fluorescence lifetimes are 4.77 ± 0.10, 4.98 ± 0.08, 5.19 ± 0.09, and 5.22 ± 0.08 ms for the In 2 O 3 specimens with 0, 0.5, 1.0, and 1.5 at% Mg 2+ doping, respectively [Fig.…”

The effects of Lu3+, Gd3+ and Ga3+ substitution on the photoluminescence of Y2.95−x−yLuxGdyAlzGa5−zO12:0.05Ce3+ phosphors for high-power white AC-LEDs

“…However, with the excessive doping of Gd 3+ ions, the phosphor will gradually possess a low content of GdAlO 3 hexagonal perovskite impurity; however, this impurity will increase the nonradiative relaxation rate and reduce the phosphor emission intensity (the Gd 3 Al 5 O 12 structure is stable at about 1300–1500 °C, but at the present operating temperature of 1600 °C, the Gd 3 Al 5 O 12 will undergo thermal decomposition to a GdAlO 3 perovskite). 34 Moreover, as the doping of Gd 3+ ions increases, it still causes 5d-orbital crystal field splitting and removes the phosphor F + -type color centers. All these reasons make the emission intensity of the phosphor reduced.…”

Nickel element doping impacts on structure features and Faraday effects of magneto‐optical transparent holmium oxide ceramics

“…Owing to the close similarities between the (0 0 1) direction for LRH and the (1 1 1) direction for oxide, the phase transformation substantially belongs to quasi‐topotactic evolution 29 . The crystallite size ( D XRD ) can be calculated from the full width at half maximum (FWHM) of the (2 2 2) diffraction band using Scherrer's equation: D XRD = Kλ /(βCos θ ), where K is the shape factor ( K = 0.89), λ is the wavelength of X‐ray ( λ = 0.15406 nm), β is the FWHM, and θ is the Bragg angle 30,31 . The determined crystallite size of the Ho 2 O 3 :1%Ni oxide powder is ∼39 nm.…”

“…where K is the shape factor (K = 0.89), λ is the wavelength of X-ray (λ = 0.15406 nm), β is the FWHM, and θ is the Bragg angle. 30,31 The determined crystallite size of the Ho 2 O 3 :1%Ni oxide powder is ∼39 nm. After high-temperature sintering, the three Ho 2 O 3 bulk specimens with 1−5 at.% Ni 2+ doping still retain the cubic crystalline phase and no trace of impurities can be observed.…”